Auxiliary service plant for aircraft



9 H. c. A. POTEZ AUXILIARY SERVICE PLANT FOR AIRCRAFT Filed May 13, 1959 4 Sheets-Sheet l mw Q Dec. 3, 1940. H. c. A. FoTEz 2,223,703

AUXILIARY SERVICE PLANT FOR AIRCRAFT Filed May 13, 1939 4 Sheets-Sheet 2 &

H Z2 Z3 Dec. 3, 1940. c POTEZ 2,223,703

AUXILIARY SERVICE PLANT FOR AIRCRAFT Filed May 13, 1939 v 4 Sheet s-Sheet 5 2 12% a Ma/ 272x 2 Dec. 3,1940.-

H. c". A. POTEZ 2,223,703

AUXILIARY SERVICE PLANT FOR AIRCRAFT Filed May 15, 1939 4 Sheets-Sheet! Patented Dec. 3, 1940 UNITED STATES PATENT OFFICE Henry Charles Alexandre Pctez, Meaulte, Somme, France A Application May 13, 1939, Serial No. 273,590

In France June 24, 1938 '8 Claims.

It is known that on board of modern aircraft there exists a great number of auxiliary devices of a most varied nature, such as a starting compressor, vacuum pumps, defrosting pumps, hy-

draulic pump generators, and the like. Such devices are operated by the engine or engines used for the flying of the aircraft. However, on board of heavy-multi-engined aircraft, in order to prevent the stopping of an engine from causing stopping of the auxiliary devices, such devices are mounted upon all the engines, or at least their operation is insured when only the minimum number of engines necessary for the sustentation of the aircraft are in operation. Moreover, in view of the constantly-increasing distance of the engines from the fuselage, it is necessary, in order to connect the auxiliary devices with the instruments, to employ .a great length of piping.

In order to obviate such drawbacks, use has 20' been made of independent plants adapted to drive the generators and the starting compressors. It was then proposed to add to these all the other auxiliary devices on board. However, this leads to a very complex aggregate of parts including the hydraulic pumps, 9. group of vacuum pumps for the defrosting, the apparatus for blind flying, a high-pressure compressor for starting, the extinguisher, the stored supply of compressed air, a mean-pressure compressor for the automatic piloting, and the generators.

The present invention has for its object to provide a central plant for aircraft including the auxiliary devices on board which are actuated by one or more auxiliary engines independent of the main engine or engines serving for the flight.

According to the invention and in order to obtain complete safety, there are provided two, separate engines adapted to drive one or more compressors as well as the generators and the hydraulic pumps, the whole plant being preferably arranged in order to provide, by suitable couplings and uncouplings, for the driving, by either one or both of the engines, of any one of the compressors or of several at the same time, and of the generators and the hydraulic pump or pumps.

In a preferred embodiment, the compressor or each compressor comprises two horizontal oppositely disposed cylinders and a third and smaller cylinder which constitutes a second stage of compression and is in line with one of the two cylinders aforesaid.

According to a further feature, each compressor fulfils one, several, or all of the following functions: the filling of a high-pressure tank for the storage of compressed air; the supply of a mean-pressure tank which is substituted for the usual compressor for the automatic piloting; the supply of a low-pressure tank which is substituted for the several usual pumps for defrosting purposes; the supply of a vacuum tank which is substituted for the several usual vacuum pumps for the blind flying apparatus; direct starting with compressed carburetted air. 1

Further characteristics will be set forth in the following description.

In the accompanying drawings, which are given solely by way of example:

Fig. l is a diagrammatic plan view of a plant in conformity with the invention, consisting of the combination of two engines with two compressors and three generators, which plant is contained in a sound-proof casing adapted to dampen the noise of the engines. 0

Fig. 2 is a, side diagrammatic view of the said plant mounted in the sound-proof casing.

Figs. 3 and 4 are a side view and an end view, with parts broken away, of an embodiment of the driving means of two compressors and a. hydraulic pump.

Fig. 5 is a diagram showing the combination of two compressors with the above-mentioned tanks and the corresponding piping.

In the diagrams shown in Figs. 1 and 2, the plant comprises two engines i and 2 having for example four cylinders each and adapted to drive respectively the gear-wheels 3 and 4 through suitable transmissions comprising clutches 5 and 6. The wheels 3 and 4 engage a gear-wheel I so that they may have the same direction of rotation although they are connected together. 'Iwo compressors C and C are driven by the wheel I through transmissions comprising clutches 8 and 9. 40

At their other ends, the engines I and 2 drive respectively two electric generators i0 and II. A third generator I! can be driven by either one of the first two generators, by means of a jawclutch l3 or the like which may connect the shaft of the generator I! either with a pulley i4 driven by a belt l5 mounted on a pulley i6 secured to the shaft of the generator III, or with a pulley ll driven by a belt mounted on a pulley l9 secured to the shaft of the generator i I.

In order to dampen the noise of the engines i and 2, the entire plant is mounted in a casing or housing 20 consisting of sound-proof material. The plant is'secured to a frame 2| (Fig. 2) which is connected with the bottom 22 of said casing by an elastic suspension device consisting of suitable parts such as springs 23. Moreover. the engines I and 2 are contained in a cowling 24. In this manner, the whole apparatus is divided into three tight compartments: a pumping compartment 26 containing the compressors C and C and the hydraulic pump or pumps, an engine compartment 26 containing the two internal combustion engines I and 2 for driving the plant and a compartment 21 for electric outfit which contains the three generators I6, I l and I2.

The arrangement of the engines 1 and 2 under the cowling and in the casing 26 makes it necessary to provide a cooling device which is particularly eflective.

For this purpose, the pumping compartment 26 is connected with the atmosphere by a sleeve 26 which may be mounted in the direction of travel of the aircraft in order to receive the relative wind V. A passage 26 connects the compartment 26 with the electric outfit compartment 21. This latter compartment is in communication with the inlet parts 36 and 3| of two blowers 32 and 33. The delivery chambers 36 and 36 of these blowers are connected respectively with spaces 36 and 31 which are closed on one side by the cylinders .of the engines I and 2 and by suitable deflectors 36 and 36 which leave a passage towards the engine compartment 36. This latter compartment is connected with the suction inlets 46 and 4| of suction fans 42 and 43, whose outlets 44 and 46 are connected with the atmosphere by a sleeve 46 whose opening is placed in the contrary direction to the travel in order to provide for a suction by the relative wind V.

Throttle-valves 41 and 46, mounted in the outlets of suction fans 42 and 43, serve to cut off these latter when the corresponding engine I or .2 is stopped.

The suction inlets 46 and 66 of the two engines I and 2 are located in the compartment 26. This compartment contains air which has been heated by its passage over the engine cylinders and at high altitudes, the carburetors of the engines are then supplied with warm air. The exhaust conduits H and 62 of the two engines I and 2 are connected with a conduit 63 mounted in the sleeve 46, whereby a depression is created at the exhaust which furthers the discharge of the burnt gas through the conduit 63.

The operation of the device described is as follows. When the engine I is running, the clutch 6 is thrown in to drive the wheel 3 which in turn drives the wheel 4 by means of the wheel 1; the clutch 6 must be disengaged in order that the engine 2, which is stopped,shall not be driven. Any device can be provided to prevent the coupling of the clutch 6 when the contact of the engine 2 is cut oil, as well as to prevent the coupling of the clutch 6 when the contact of the engine I is cut oil. This allows of driving the compressor C or the compressor C or both at the same time, by coupling the clutch 6 or the clutch 6, or both together. In like manner, if the engine 2 is running and the engine I stopped, with clutch 6 thrown in and clutch 6 thrown off, the compressors O and C can be driven at the same time or separately, by means of the clutches 6 and 6. The engines I and 2 can also be used at the same time. (It should be noted that a like arrangement can be employed for any number of engines).

The cooling is insured by the blowers 32 and 33 and the suction fans 42 and 43, which are driven respectively by the engines I and 2. The cooling air enters at 26 into the pumping compartment 26 where it cools the compressors C and C, it then proceeds through the passage 26 into the compartment 21 in which it cools the'generators I6, II and I2, and is then withdrawn at 36 and 3I by the blowers 32 and 33 which deliver it into the spaces 36 and 31, and passes thence between the deflectors 36 and 36 and the cylinders of the engines I and 2, thus cooling these latter. The air is now contained in the engine compartment 26, from which it is withdrawn, on the one hand by the suction inlets 46 and 66 of the engines I and 2, and on the other hand by the suction fans 42 and 43 which discharge it into the atmosphere through the sleeve 46. If one of the engines were stopped, the corresponding throttle valve 41 or' 46 will be closed in order to prevent a part of the air from being circulated on a closed circuit through 36, 44, 46, H and 36, or inversely, according as the engine I or the engine 2 is stopped.

Figs. 3 and 4 are detail views showing a preferred embodiment of the connections between the engines and the compressors C C'. In this embodiment, the engines I and 2 drive respectively pulleys 64 and 66, which in turn drive through belts 66 and 61 and pulleys 66 and 66 the shafts 66 and 6| journalled in bearings 62 and 63- of a cover 64 mounted on the casing or gear-box 66. The driving parts of the clutches 6 and 6 are secured to the shafts 66 and 6| and pulleys H and 12 which are connected by belts 13 and 14 with pulleys 16 and 16 mounted on the crankshafts 11 and 16 of the compressors C and C", respectively. The said crankshafts 11 and 18 arerotatable respectively in bearings 16 and 66 on the casings 6I and 62 of the compressors C and C which are mounted on the casing 66. Upon the said casings 6| and 62 are mounted horizontally and in the opposite position the cylinders 63 and 64, a small cylinder 66 being mounted on the cylinder-heads of the cylinders 64 in line with the same and inthe horizontal position. The cylinders 63 and 64 are oppositely situated, and their pistons are driven by a crankshaft having two crank-pins spaced at but any other arrangement of cylinders and crank-pins can be employed, although the present arrangement is the best as concerns the balancing. The piston of the cylinder 66 is connected with the piston of the cylinder 64 and follows it in its movements, the connection being such that the lateral reactions of this latter piston will not be imparted to the piston of the cylinder 66 with which it is connected.

The pinions 3 and" 4 engage a gear-wheel 66 which is keyed to a shaft 61 rotatable in bearings 66 secured to the casing 66, and drives the hydraulic pump 66 which may serve for the actuation of the retraction jacks of the landing gear.

Lugs 66 serve to secure the casing or gear-box 66 to the frame 6|.

The compressors C and C are preferably combined, as shown in Fig. 5, with:

A vacuum tank 66 which is substituted for the vacuum pumps for the actuation of the blind flying apparatus;

A low-pressure tank 90 supplying the defrosting circuits;

A mean-pressure tank 91 for the requirements of the automatic piloting device.

A high-pressure tank 90 which serves as a storage supply of compressed air.

Regulating valves 99 are mounted on the tanks 95, 96 and 91. The valve of the tank 91 can deliver into the tank 90 through a conduit I00, but this is not obligatory. Each tank is provided with a pressure-gauge NH and a valve I02 for intake and ofltake.

Both compressors C and C are connected in parallel with these tanks. The suction inlet of the cylinder 03 of each compressor is connected with a distributer I 03 which provides for withdrawal from the atmosphere at I04, or through a carbureter I05. Its discharge outlet is connected with a distributer I by which compressed air can be circulated into the high-pressure tank 98 through the conduit I01, or into the starting distributer through I08, or into the low-pressure tank 98 through the conduit I09, or to the atmosphere outlet at IIO. Checkvalves III are mounted on the said conduits I01 and I09. a

The suction of each cylinder 84 takes place through the vacuum tank 95 through the conduit H2, and the discharge outlet of each cylinder 84 is connected with the low-pressure tank 96 through the conduit II3.

Each cylinder 85 withdraws in the tank 96 through the conduit II I, and discharges into the mean-pressure tank 9I through the conduit H5.

The operation of the device is as follows. The pistons of the cylinders 03, 84, 95 are driven by the crankshaft 11 or I8. When it is desired to start the engines for the propulsion of the aircraft, the distributer I03 provides for the suction of air through the starting carbureter I05, and the cylinder 83 of either one or both of the compressors will discharge this carburetted air into the starting circuit, through the distributer E08 and the conduit I08.

For defrosting purposes, the distributer I03 is turned for connection with the atmosphere at I04. The cylinder 83 thus withdraws at atmosphere pressure and discharges'through the distributer Hi6 into the low-pressure tank 96; the cylinder 84 also discharges into the tank 96 and withdraws air from the vacuum tank 95, thus producing a constant vacuum in the latter, owing to the valve IN. This vacuum may serve for the actuation of the blind flying apparatus when the corresponding valve I02 is open. When the valve I02 of the tank 96 is open, the defrosting circuit can be supplied. If the output is excessive, or if the valve I02 of this tank is closed and no defrosting action is required, the distributer I06 permits of connecting the discharge outlet of the cylinder 03 with the atmosphere at IIO.

In order to operate the automatic piloting device, this is effected by opening the cock I02 of the mean-pressure tank 91 which is supplied by the discharge from the cylinder 85 which withdraws from the low-pressure tank 96. When the valve I02 of the tank 91 is closed, the valve 99 of this tank will open, and thus the air in the tank 91 will expand and will flow into the lowpressure tank 99.

Finally, when it is desired to set the storage tank 90 under pressure, the discharge from the cylinder 89 is connected withthis tank by the distributer I08, the distributer I03 being still connected with the atmosphere for the suction.

Obviously, the said invention is not limited to the embodiments herein described and represented, which are given solely by way of example.

Having now described my invention, what I claim as new and desire to secure by Letters Patent is:

1. In a central plant for auxiliary services on board of aircraft, the combination of two independent internal combustion engines, at least two air compressors, electric generators, at least one hydraulic pump, and means for operatively connecting in a selective manner either one or both of said engines to either one or both of said air compressors, to said electric generators and to said hydraulic pump.

2. In a central plant for auxiliary services on board of aircraft, the combination of two internal ccmbusion engines, two gear-wheels, separate driving connections between each of said engines and one of said gear-wheels, respectively, each of said driving connections including a clutch having a driving member operatively connected to the respective engine and a driven member operatively connected to said gear-wheel, a toothed pinion meshing with both gear-wheels, two air compressors, and separate transmission means between said toothed pinion and each of said compressors and including a clutch having a driving member operatively connected to said pinion and a driven member operatively connected to the respective compressor.

3. A plant as claimed in claim 2, further comprising two other gear-wheels each of which is mounted coaxially with and is connected in rotation to one of said first-mentioned gear-wheels, respectively, a second toothed pinion meshing with both of said other gear-wheels and a hydraulic pump driven by said second pinion.

4. In a central plant for auxiliary services on board oi aircraft, the combination of two electric generators, an internal combustion engine combined with each electric generator for driving same, a third electric generator, and means for selectively coupling said third generator to either one of said two first mentioned generators.

5. A central plant for auxiliary services on board of aircraft comprising auxiliary service devices including two air compressors, electric generators, and a hydraulic pump, internal combustion engines for driving said auxiliary service devices, and a sound-proof casing enclosing said auxiliary service devices and said internal combustion engines, said auxiliary service devices and said internal combustion engines being supported elastically within said casing which is provided with an inlet for cooling air and with an outlet for this air.

6. A central plant for auxiliary services on board of aircraft, comprising air and hydraulic pumps, electric generators and internal combustion engines for driving said pumps and said generators, a common casing enclosing all the abovementioned parts, partitions in said casing for dividing the latter into three compartments, a first compartment containing the pumps, a second compartment containing said generators and a third compartment containing said engines, said first compartment being provided with an air inlet which is open to the atmosphere in the direction of travel of the aircraft, a passage connecting 4 amsnos said first compartment with said second compartment, engine-driven blowers withdrawing air from said second compartment and discharging it into. said third compartment onto the hot parts 01' said engines for cooling same and suction tans withdrawing air from said third compartment and discharging into the atmosphere outside of said casing.

7. A plant as claimed in claim 6, in which said engines have a plurality oi cylinders arranged in rows and further comprising means for guiding the'air discharged by said blowers across said rows of cylinders.

8. A plant as claimed in claim 6, in which 6 each of said suction fans is provided with a valve for throttling the discharge.

HENRY CHARLES ALBDIANDRE POTEZ. 

